Method and apparatus for cold bending h-shaped steel

ABSTRACT

A method and apparatus for bending a grooved, H-shaped or the like shaped steel workpiece having a center web and two parallel flanges extending at right angles to and connected by the web in the plane of the web by cold-bending in which the inner surface of one of the two flanges has applied thereon an outward force by a pressure roller means and the inner surface of the other flange also has applied thereon an outward force by a pair of spaced pressure receiving roller means positioned on the opposite sides of the pressure roller means whereby the shaped steel workpiece has imparted thereto a bending moment without applying any buckling load on the web across the width thereof and the workpiece is then transferred in the longitudinal direction thereof with the workpiece held in pressure contact with the rollers.

United States Patent [191 Yashiro 11] 3,826,121- [451 July 30, 1974METHOD AND APPARATUS FOR COLD BENDING H-SHAPED STEEL [76] Inventor:Kazuyoshi Yashiro, No. 19

Miharashi-cho 2-chome, Kue-shi, Hiroshima-kemlapan [22] Filed: -Feb. 27,1973 [21] Appl. No.: 336,350

[52] US. Cl. 72/170, 72/171 [51] Int. Cl B21d 5/14 [58] Field of Search72/170-l75 [56] References Cited 1 UNITED STATES PATENTS 2,279,1974/1942 Hoell 72/171 2,767,767 10/1966 Peterson 72/170 X 3,339,392 9/1967Buckwalter et a1 72/170 X FOREIGN PATENTS OR APPLICATIONS 19,988 8/1969Japan 72/173 Primary ExaminerMilton S. Mehr Attorney, Agent, orFirm-Wenderoth, Lind & Ponack [57] ABSTRACT A method and apparatus forbending a grooved, H- shaped or the like shaped steel workpiece having acenter web and two parallel flanges extending at right angles to andconnected by the web in the plane of the web-by cold-bending in whichthe inner surface of one of the two. vflanges has applied thereon anoutward force by a pressure roller means and the inner surface of theother flange also has applied thereon an outward force by a pair ofspaced pressure receiving roller means positioned on the opposite sidesof the pressure roller means whereby the shaped steel workpiece hasimparted thereto a bending moment without applying any buckling load onthe web across the width thereof and the workpiece is then transferredin the longitudinal direction thereof with the workpiece held inpressure contact with the rollers.

4 Claims, 5 Drawing Figures PATENTEU L 3.826. 1 2 1 Fig fi'? ART F/g. 2PRIOR ART METHOD AND APPARATUS FOR COLD BENDING II-SHAPED STEELBACKGROUND OF THE INVENTION This invention relates to a method andapparatus for bending a shaped steel workpiece and especially, an H-shaped or grooved steel workpiece having a center web and two parallelflanges extending at right angles to and connected by the web in theplane of the web by coldbending.

A number of methods for bending an H-shaped steel workpiece or the likehaving a center web and parallel flanges extending at right angles toand connected by the web in the plane ofthe web by cold-bending havebeen proposed and practically employed. Such prior art methods may begenerally exemplified as follows: a. A first prior art method Accordingto this method, the center web of a shaped steel workpiece such as anI-I-shaped steel workpiece is cut off or sheared in the axial direction(longitudinal direction) thereof to divide the workpiece into two halfportions, the half portions are individually bent to a desired curvaturein the plane of the web thereof by a conventional bender andthereafter,.the bent half portions are welded together along thelongitudinal cut faces thereby to obtain an H-shaped on the like shapedsteel workpiece product having the desired curvature. Alternatively, twopreformed T-shaped or L-shaped steel workpieces are bent to a desiredcurvature in-the plane of the web thereof and the'workpieces are thenwelded together at their legs thereby to obtain an H- shaped or agrooved steel product having the desired curvature.

b. A second prior artmethod According to this method, the opposite endsof a shaped steel workpiece are pulled by a stretcher against dies to adesired or necessary curvature or shape.

c. A third prior art method According to this method, the outer surfaceof one of the two flanges of a shaped steel workpiece such as anH-shaped steel workpiece is supported on apair of spaced pressurereceiving rollers whereas the outer surface of the other flange hasapplied thereto an inward force by a single pressure roll in anintermediate position between the pair of pressure receiving rollers andthe workpiece is then bent in the plane of the web thereof as theworkpiece is transferred in the longitudinal direction thereof whilebeing held in pressure contact with the rollers.

However, the first prior art method includes the welding operation whichconsumes a great deal of labor and time and since the obtained shapedsteel product has the welded joint, the strength of the product isfrequently insufficient for application as a structural member. In thesecond prior art method, the opposite ends of the shaped steel workpiecewhich have been gripped by jaws of the stretcher will be damaged to adegree that they become unserviceable and the damaged end portions haveto be removed resulting in waste of material. In the third prior artmethod, the center web of the shaped steel workpiece is subjected to acompressive (buckling) load across its width which will buckle the weband the opposite flanges are also easily subjected to deformation.Therefore, the curvature range obtainable by this method is limited to arelatively narrow one.

SUMMARY OF THE INVENTION Therefore, one object of the present inventionis to provide a method for cold-bending a shaped steel workpiece in theplane of the web thereof which can effectively eliminate the timeconsuming operation inherent in the above-mentioned first and secondprior art methods and which includes the bending operation utilizingonly the rollers as in the case of the third prior art method, but whicheliminates the possibility of the buckling and/or deformation whichinevitably occurs in the third prior art method.

According to one embodiment of the present invention, pressure andpressure receiving rollers are employed as in the case of the thirdprior art method as means for applying pressure against a workpiece, buta pressure roller means and a pressure receiving roller means applyoutward forces on the flanges of a shaped steel workpiece from the innersurface of the flanges instead of merely applying pressure on theflanges from the outer surfaces thereof as in the case of the thirdprior art method and the pressure roller means and pressure receivingroller means apply such outward forces in opposite directions so thatthe workpiece has imparted thereto a bending moment with no compressive(buckling) load applied on the center web across its width and theworkpiece-is then bent in its web plane by cold-rolling as theworkpiece'is transferred in the longitudinal direction while being heldin pressure contact with the roller means.

Thus, according to the present invention, a shaped steel workpiece canbe easily and rapidly processed while eliminating the possibility of thebuckling of the center web and/or the deformation of the flanges whichinevitably occur in the prior art corresponding methods.

Anotherobject of the present invention is to provide an apparatus forcarrying out the method.

The above and other objects and attendant advantages of the presentinvention will be more apparent to those skilled in the art from areading of the following detailed description in conjunction with theaccompanying drawing which shows preferred embodiments of the inventionfor illustration purpose only, but not limiting the scope of the same inany way.

BRIEF DESCRIPTION OF THEDRAWING FIG. 1 is a perspective view showing theabovementioned third prior art method for curving a workpiece in theplane of the web thereof by cold-bending;

FIG. 2 is an end elevational view of FIG. 1;

FIG. 3 is a front elevational view showing one embodiment for bending aworkpiece in the plane of the for web thereof by cold-bending accordingto the present DETAILED DESCRIPTION OF THE PRESENT INVENTION For betterunderstanding of the advantages of the present invention over the priorart, a description will first be given of FIGS. 1 and '2 of theaccompanying drawing which show the above-mentioned third prior artmethod for bending a shaped workpiece in the plane of the web thereof bycold-bending. In these Figures, the prior art method is shown as beingapplied to the bending of an H-shaped steelworkpiece 10 which has a pairof opposite parallel flanges 11 and 12 and a web 13 extending betweenthe flanges at right angles thereto and connecting them together. Inbending the I-I-shaped steel workpiece 10 in the plane of the web bycold-bending, a pressure roller 14 is brought into pressure-contact withthe outer or upper surface 11' of the flange l1 and a pair of spacedpressure receiving rollers 14' and 14' are brought into pressure-contactwith the outer or lower surface 12 of the flange 12 and support theworkpiece 10 from below whereby the workpiece has pressure appliedthereto from both above and below. While being held in pressure-contactby the rollers, the workpiece 10 is bending inwardly or rearwardly asseen in FIG. 1 in the plane of the web as the workpiece is transferredin the longitudinal direction thereof (as indicated by the arrow A inFIG. 1). However, the prior art cold-bending method has the disadvantagethat the flanges 11 and 12 of the workpiece 10 are likely to deformdownwardly and/or upwardly, and the center web will be buckled as shownby the broken lines in FIG. 2 while the workpiece is being processed.

FIGS. 3 to 5 inclusive show preferred embodiments of the presentinvention in which the method of the invention is shown as being appliedto the bending of H- shaped steel workpieces (identical with that shownin FIGS. 1 and 2) in the plane of the web thereof by coldbending forillustration purpose only, but the method of the invention can beequally applied to other shaped steel workpieces to be similarlyprocessed.

Reference will be first had to FIGS. 3 and 4 which show a firstembodiment of the invention. In carrying out the method of theinvention, a pair of spaced pressure receiving rollers 20 are broughtinto pressurecontact with the inner surface 11" of the flange 11 of theworkpiece on each side of the center web 13 of the workpiece spaced fromthe flange l2 and a pressure roller 21 is brought into pressure-contactwith the inner surface 12" of the flange 12 a position between thepressure receiving rollers on each side of theweb l3 spaced from theflange 11.

With the above arrangement of pressure rollers and pressure receivingrollers, the two types of rollers cooperate with each other to applyoutwardly directed forces in the opposite directions against the innersurfaces 11" and 12" of the opposite flanges 11 and 12 of the workpiecel0. Thereafter, in bending the workpiece 10 in the plane of web thereofby cold-bending, the workpiece is transferred in its longitudinaldirection relative to the rollers 20 and 21 with held in pressurecontactby the rollers. For transferring the workpiece 10 in the mannerdescribed above, the rotary shafts of the rollers 20 and 21 arepreferably connected to a prime mover (not shown) by means of gearing orthe like (not shown) so as to rotationally drive the rollers. However,alternatively, the workpiece 10 can be also transferred by pulling theworkpiece with a separate pulling means (not shown) which operatesindependently of the rollers.

The force which holds the pressure rollers and pressure receivingrollers in pressure-contact with the respectively associated flanges ofthe workpiece is preferably supplied from a suitable hydraulic fluiddevice, but any conventional pressure applying device can be employed incarrying out the invention.

According to the embodiment of the invention as just describedhereinabove, in contrast with the prior art method as shown in anddescribed in connection with FIGS. 1 and 2 hereinabove, since nobuckling load is applied on the center web 13 of the workpiece 10 acrossthe width of the web, the web will not buckle in its width direction andin addition, since the flanges l1 and 12 of the workpiece 10 will befree of any buckling load, the flanges can also be effectively protectedfrom deformation. 7

Thus, according to the present invention, the workpiece can be bent,without causing any drawback such as that of the prior art, in the planeof the web thereof by cold-bending to a relatively great curvature.

Referring now to FIG. 5 which shows another embodiment of the invention.The embodiment of FIG. 5 is a combination of the prior art of FIGS. 1and 2 and the embodiment of FIGS. 3 and 4. As shown in FIG. 5, a pair offirst spaced pressure receiving rollers 20a are brought intopressure-contact with the inner surface 11 of the flange 11 of theworkpiece 10 on each side of the center web 13, a first pressure roller21a is brought into pressure-contact with the inner surface 12" oftheflange 12 at a position between the pressure receiving rollers 20a oneach side of the web as in the case of the embodiment of FIGS. 3 and 4,a pair of second spaced pressure rollers 20b are brought intopressure-contact with the outer surface 12' of the flange 12 inpositions corresponding to the first pressure receiving rollers 20a anda second pressure roller 21b is brought into contact with the outersurface 11 of the flange 11. Thus, it will be understood that the firstand second pressure rollers 21a and 21b apply forces against the flanges11 and 12 in the same direction and similarly, the first and secondpressure receiving rollers 20a and 20b apply forces against the flanges11 and 12 in the same direction, but the force applying direction of thepressure rollers is the opposite of that of the pressure receivingrollers. After the rollers have been positioned on the workpiece 10 inthe manner as described above, the workpiece is transferred in thelongitudinal direction to be subjected to the bending process bycold-rolling as in the case of the embodiment of FIGS. 3 and 4.

In contrast to the above-mentioned third prior art method in which thepressure necessary for curving the workpiece in its web plane is appliedon only the outer surfaces of the two flanges of the workpiece,accordingto the embodiment of FIG. 5, such pressure is also applied onthe inner surfaces of the flanges of the workpiece as well as the outersurfaces of these flanges and thus, the embodiment of FIG. 5 cansubstantially reduce the compressive (buckling) load on the center webof the workpiece which was great in the prior art method as referred tohereinbefore and in consequence, the embodiment of this Figure caneliminate or substantially reduce the problem of the buckling of thecenter web and/or deformation of the flanges of the workpiece and makesit possible to bend the workpiece in the plane of the web with arelatively greater curvature than that possible by the prior artmethods.

The ratio of the pressure applied by the first pressure rollers to thatby the second pressure roller and the ratio of the first pair ofpressure receiving rollers and that by the second pair of pressurereceiving rollers can be selectively determined depending upon the shapeand size of the particular steel workpiece to be processed and thedesired curvature for the product to be obtained from the workpieceafter the same has been processed by the present invention. It has beenexperimentally found that the curvature obtainable by the presentinvention is about two times as great as that obtainable by the priorart methods by properly selecting the values of factors, such asreferred to above, concerned.

While only two preferred embodiments of the invention have been shownand described in detail for illustration purpose only, they are not tobe taken as a definition of the invention, reference being had for thispurpose to the appended claims.

What is claimed is:

l. A method for bending by cold bending a shaped steel workpiece such asa grooved or H-shaped steel workpiece having a center web and a pair ofparallel flanges at the opposite ends of said web and connected therebyin the plane of the web of said workpiece, comprising the steps of a.applying a first outward pressure against a first flange on the innersurface thereof by a pressure roller means;

b. applying a second outward pressure against a second flange on theinner surface thereof by a pair of pressure receiving roller meanspositioned at positions spaced along the workpiece and on the oppositesides of said pressure roller means, said second outward pressure beingin the opposite direction from the pressure applied against said firstflange; and

c. transferring said workpiece in the longitudinal direction thereofwhile it is held in pressure-contact with said roller means for bendingsaid workpiece in its center-web plane in the direction of said secondoutward pressure by cold-bending.

2. The method as set forth in claim 1, further including the steps of:

a. applying a first inward pressure against said second flange on theouter surface thereof by a second pressure roller in a position alongthe workpiece corresponding to that at which said first outward pressureis applied and in the same direction as said first outward pressure; and

b. applying a second inward pressure against said first flange on theouter surface thereof by a second pair of pressure receiving rollers inpositions along the workpiece corresponding to that at which said secondoutward pressure is applied in the same direction as said second outwardpressure.

3. The method as set forth in claim 1, in which the workpiece is anl-l-shaped steel workpiece which is to be bent in the plane of the webthereof by coldbending, and the first and second outward pressures areapplied to the inner surface of said first and second flanges on theopposite sides of said center web of the H-shaped steel workpiece.

4. An apparatus for carrying out cold bending of a shaped steelworkpiece such as a grooved or H-shaped steel workpiece having a-centerweb and a pair of parallel flanges at the opposite ends of said web andconnected thereby in the plane of the web of the workpiece comprising:

a. a pressure roller means adapted to be brought into pressure-contactwith the inner surface of one of the two flanges of the shaped steelworkpiece for applying a first outward pressure against said one flange;

b. a pair of pressure receiving roller means on opposite sides of saidpressure roller means and spaced therefrom in the direction of thelength of the workpiece and adapted to be brought into pressure-contactwith the inner surface of the other flange of said workpiece forapplying a second outward pressure against said other flange; and

0. means for transferring said workpiece in the longitudinal directionthereof with the workpiece held in pressure-contact with said rollermeans.

1. A method for bending by cold bending a shaped steel workpiece such asa grooved or H-shaped steel workpiece having a center web and a pair ofparallel flanges at the opposite ends of said web and connected therebyin the plane of the web of said workpiece, comprising the steps of a.applying a first outward pressure against a first flange on the innersurface thereof by a pressure roller means; b. applyiNg a second outwardpressure against a second flange on the inner surface thereof by a pairof pressure receiving roller means positioned at positions spaced alongthe workpiece and on the opposite sides of said pressure roller means,said second outward pressure being in the opposite direction from thepressure applied against said first flange; and c. transferring saidworkpiece in the longitudinal direction thereof while it is held inpressure-contact with said roller means for bending said workpiece inits center-web plane in the direction of said second outward pressure bycold-bending.
 2. The method as set forth in claim 1, further includingthe steps of: a. applying a first inward pressure against said secondflange on the outer surface thereof by a second pressure roller in aposition along the workpiece corresponding to that at which said firstoutward pressure is applied and in the same direction as said firstoutward pressure; and b. applying a second inward pressure against saidfirst flange on the outer surface thereof by a second pair of pressurereceiving rollers in positions along the workpiece corresponding to thatat which said second outward pressure is applied in the same directionas said second outward pressure.
 3. The method as set forth in claim 1,in which the workpiece is an H-shaped steel workpiece which is to bebent in the plane of the web thereof by cold-bending, and the first andsecond outward pressures are applied to the inner surface of said firstand second flanges on the opposite sides of said center web of theH-shaped steel workpiece.
 4. An apparatus for carrying out cold bendingof a shaped steel workpiece such as a grooved or H-shaped steelworkpiece having a center web and a pair of parallel flanges at theopposite ends of said web and connected thereby in the plane of the webof the workpiece comprising: a. a pressure roller means adapted to bebrought into pressure-contact with the inner surface of one of the twoflanges of the shaped steel workpiece for applying a first outwardpressure against said one flange; b. a pair of pressure receiving rollermeans on opposite sides of said pressure roller means and spacedtherefrom in the direction of the length of the workpiece and adapted tobe brought into pressure-contact with the inner surface of the otherflange of said workpiece for applying a second outward pressure againstsaid other flange; and c. means for transferring said workpiece in thelongitudinal direction thereof with the workpiece held inpressure-contact with said roller means.